fix #1691 drawTransparentCircleHole bug

[liuxuan30]

fix #1691

1. M_PI_2 is Pi / 2, not Pi * 2

   public var M_PI_2: Double { get } /* pi/2 */

2. clockwise in UIKit and CoreGraphics is flipped(compared to UIBezierPath), though 0 to M_PI * 2 does not get affected by clockwise.

   The clockwise parameter determines the direction in which the arc is created; the actual direction of the final path is dependent on the current transformation matrix of the graphics context. For example, on iOS, a UIView flips the Y-coordinate by scaling the Y values by -1. In a flipped coordinate system, specifying a clockwise arc results in a counterclockwise arc after the transformation is applied.

3. using even odd rule to fill between two arcs, not default.

BTW, I hate the new Apple API doc:(
The mentioned APIs above do not have any words, while the old doc has rich information. Have to use CGContextAddArc etc. to get the discussion

[liuxuan30]

test code (replace setDataCount in LineChart1ViewController):

- (void)setDataCount:(int)count range:(double)range
{
    NSMutableArray *values = [[NSMutableArray alloc] init];

    for (int i = 0; i < count; i++)
    {
        double val = arc4random_uniform(range) + 3;
        [values addObject:[[ChartDataEntry alloc] initWithX:i y:val]];
    }

    LineChartDataSet *set1 = nil;
    if (_chartView.data.dataSetCount > 0)
    {
        set1 = (LineChartDataSet *)_chartView.data.dataSets[0];
        set1.values = values;
        [_chartView.data notifyDataChanged];
        [_chartView notifyDataSetChanged];
    }
    else
    {
        set1 = [[LineChartDataSet alloc] initWithValues:values label:@"DataSet 1"];

        [set1 setHighlightColor:[UIColor clearColor]];
        set1.drawValuesEnabled = NO;
        set1.drawCirclesEnabled = YES;
        set1.circleHoleColor = [UIColor clearColor];
        set1.circleColors = [NSArray arrayWithObject:[UIColor orangeColor]];
        set1.circleHoleRadius = 7.0f;
        set1.circleRadius = 8.0f;
        set1.colors = [NSArray arrayWithObject:[UIColor blueColor]];

        NSMutableArray *dataSets = [[NSMutableArray alloc] init];
        [dataSets addObject:set1];

        LineChartData *data = [[LineChartData alloc] initWithDataSets:dataSets];

        _chartView.data = data;
    }
}

[codecov-io]

Current coverage is 18.68% (diff: 0.00%)

Merging #1711 into master will not change coverage

@@             master      #1711   diff @@
==========================================
  Files           123        123          
  Lines         14052      14052          
  Methods           0          0          
  Messages          0          0          
  Branches          0          0          
==========================================
  Hits           2626       2626          
  Misses        11426      11426          
  Partials          0          0          

Powered by Codecov. Last update 8ef870a...6798bc8

[codecov-io]

Current coverage is 18.68% (diff: 0.00%)

Merging #1711 into master will not change coverage

@@             master      #1711   diff @@
==========================================
  Files           123        123          
  Lines         14052      14052          
  Methods           0          0          
  Messages          0          0          
  Branches          0          0          
==========================================
  Hits           2626       2626          
  Misses        11426      11426          
  Partials          0          0          

Powered by Codecov. Last update 8ef870a...33f63ac

[liuxuan30]

@petester42 did you changed any config? Last week it still failed, but I restarted it today and it passes!

[pmairoldi]

I havent fixed it yet but I know why it fails. For pull requests the github token doesn't get used in the build. Because of this we hit the limit sometimes.

[liuxuan30]

but it somehow passed.. randomly

[danielgindi]

This does not fix the hole thing for me...

[liuxuan30]

Oh no. Which part of the hole?
It' fine on my side:

if revert back: